Biomedical subjects

Y F Lin

Publications and source records attributed to Y F Lin.

At least 73 records · Page 4Linked to original sources

PubMed1994

Hyperparathyroidism, glucose tolerance and platelet intracellular free calcium in chronic renal failure.

Disturbance in the vitamin D/parathyroid hormone (PTH) axis may be important in the pathogenesis of glucose intolerance and insulin resistance in uraemia. To investigate possible relationships between hyperparathyroidism, intracellular free calcium ([Ca2+]i), and glucose tolerance in chronic renal failure, we measured serum intact PTH (I-PTH) by two-site immunometric assay, platelet [Ca2+]i using the fluorescent indicator fura-2, and plasma glucose and insulin after 14 h overnight fast and at 30, 60 and 120 min following a 75 g oral glucose load, in 18 chronic haemodialysis patients with elevated serum I-PTH. Calcitriol (1 microgram) was administered parenterally at the end of each dialysis session for four weeks. This significantly decreased serum I-PTH (p < 0.001) and platelet [Ca2+]i (p < 0.01). Uraemic patients initially showed marked glucose intolerance, with increased area below the glucose curve compared to healthy controls, but after 4 weeks of calcitriol treatment, this effect was significantly decreased, and there was a significant rise in the area under the insulin curve after glucose load. The insulinogenic index also increased significantly after calcitriol treatment. These data suggest that calcitriol treatment of haemodialysis patient with secondary hyperparathyroidism is associated with increased insulin secretion in response to glucose challenge, and that this change is linked to the decrease in intracellular free calcium.

Adult↗

PubMed1993

Retinoic acid biphasically regulates the gene expression of hepatitis B virus surface antigen in human hepatoma Hep3B cells.

We used human hepatoma Hep3B/C16 cells as a model to examine the effect of all-trans retinoic acid on the gene expression of hepatitis B surface antigen (HBsAg). Hep3B/C16 is a clonal derivative of human hepatoma Hep3B cell which was stably transfected with HBsAg DNA sequences and can produce hepatitis B virus surface antigen. We analyzed the HBsAg product and mRNA in Hep3B/C16 cells which were exposed to retinoic acid for different periods of time. The level of HBsAg started to increase after 24 h and reached maximum at 48 h of retinoic acid treatment. However, the level of HBsAg expression was severely suppressed compared to the control cells after long term (120 h) retinoic acid treatment. Such biphasic regulation of HBsAg production by retinoic acid was paralleled by the changes of HBsAg mRNA. Nuclear run-on assays also demonstrated that the retinoic acid-mediated regulation was determined at least in part at the transcriptional level. Furthermore, an exposure of the cells to retinoic acid for only 8 h was sufficient to show that up- and down-regulation of HBsAg gene occurred 2 and 5 days later. Using a transient expression system, we demonstrated that the retinoic acid response element is located within the 5'-flanking region of the HBsAg gene.

Gene Expression Regulation, Viral↗

PubMed1993

Measuring lidocaine metabolite--monoethylglycinexylidide as a quantitative index of hepatic function in adults with chronic hepatitis and cirrhosis.

Lidocaine is metabolized to form monoethylglycinexylidide (MEGX) via oxidative N-deethylation in the liver. To assess the clinical value of this lidocaine metabolite as a quantitative liver function test, we measured the serum MEGX concentration 15 min after intravenous administration of a single dose of lidocaine (1 mg/kg) in 24 adults with chronic hepatitis, 47 patients with cirrhosis and 26 normal controls. A fluorescence polarization immunoassay was used to obtain the MEGX value. The MEGX concentration in controls was 67 (54-95) ng/ml (median with 16th-84th percentile in parentheses), which was higher than 43 (23-61) ng/ml in patients with chronic hepatitis and 24 (7-52) ng/ml in those with cirrhosis (P < 0.05). In addition, the serum MEGX levels are proportional to the galactose elimination capacity, and inversely proportional to Pugh's score, the prothrombin time and indocyanine green retention ratio. If a MEGX concentration of below 54 ng/ml is taken as an indicator of hepatic dysfunction, its diagnostic sensitivity for hepatic disorder is 84.5%, specificity 88.5% and accuracy 85.6%. Furthermore, after a 10-month follow-up, patients with MEGX formation above 30 ng/ml had a higher survival rate than those with a MEGX concentration below this level (P = 0.004). In conclusion, the MEGX formation test reflects the severity of hepatic dysfunction quite well, making it valuable both in the quantitative evaluation of liver function and in the prognostic prediction of adults with liver diseases.

Adult↗

PubMed1993

Adrenergic regulation of renin secretion and renal hemodynamics during deliberate hypotension in humans.

To assess the relative contributions of neural and nonneural stimuli of renin secretion, the effects of an alpha 1-agonist, phenylephrine (Phe), or a beta-agonist, epinephrine (Epi), on plasma renin activity (PRA), renal blood flow (RBF), and glomerular filtration rate (GFR) were compared during sympathetic blockade with epidural hypotensive anesthesia [mean arterial blood pressure (MAP) = 60 and 50 mmHg]. Controls (NaCl) received saline alone to maintain MAP at 50 mmHg. Epi increased PRA (ng.ml-1.h-1) from 0.9 +/- 0.6 to 3.0 +/- 1.5 at 60 mmHg MAP and 4.7 +/- 1.8 at 50 mmHg MAP, with associated decreases in RBF (-33 and -60%, respectively) and GFR (-27 and -53%, respectively). During hypotension with Phe and NaCl, PRA and RBF were unchanged from baseline but GFR decreased. Urinary Na secretion decreased comparably in all three groups. In conclusion, during sympathetic blockade with epidural anesthesia, marked reductions in both renal perfusion pressure and distal nephron Na delivery were insufficient to increase renin secretion. beta-Adrenergic stimulation (e.g., Epi) was required to increase PRA. Epi decreased RBF suggesting an angiotensin II-mediated effect.

Anesthesia, Epidural↗

PubMed1993

Serum osteocalcin and vitamin D in postmenopausal diabetic azotemics.

To clarify the role of serum vitamin D and bone remodeling markers in postmenopausal diabetic azotemics, we designed a study involving 3 different postmenopausal patient groups. Group I consisted of 20 diabetic women with renal insufficiency who were not yet on dialysis therapy. Group II consisted of 15 age-matched nondiabetic women with comparable degrees of renal insufficiency. Group III consisted of 20 age-matched women with normal renal function. We investigated the overnight fasting serum 25 (OH) vit-D, 1,25(OH)2 vit-D3, osteocalcin (OC), bone isoenzyme of alkaline phosphatase (ALK-PB) and intact parathyroid hormone (I-PTH) levels in these cases. The serum I-PTH and OC levels were statistically significantly higher, whereas 1,25(OH)2vit-D3 were significantly lower in Group I and Group II patients than in Group III patients. We found no significant correlation between elevation of I-PTH and reduced 1,25(OH)2 vit-D3 levels in Group I and Group II patients. I-PTH levels correlated positively with OC in Group I and Group II patients. There was no significant difference in serum 25(OH) vit-D among these 3 groups of patients. We conclude that (1) serum OC level may serve as a good parameter in evaluating secondary hyperparathyroidism in postmenopausal azotemics with or without diabetes, (2) even in the presence of menopause, renal failure per se is the main factor in determining serum 1,25(OH)2 vit-D3 levels in diabetic azotemics.

Aged↗

PubMed1993

Study on morphology of mandibular corpus and ramus influencing the eruption of mandibular first permanent molar.

The mandibular first permanent molar has been reported to be the first permanent tooth to erupt. However, according to the recent reports, a considerable increase in the number of children has been observed with the eruption of the mandibular first permanent molar after the eruption of the mandibular central incisor. The purpose of this study is to investigate whether there is any morphological difference in the mandible including the mandibular corpus and the ramus between the subjects with the mandibular first permanent molar erupting prior to the mandibular central incisor (Group A) and the subjects with the mandibular central incisor erupting prior to the mandibular first permanent molar (Group B). Lateral, posteroanterior, 45-degree oblique cephalometric radiographs and dental plaster models were used as the materials. Based on the data statistically analyzed, the results are summarized as follows: 1. No significant differences were found in the conventional angular lateral cephalometric measurements between the two groups. 2. No significant difference was found in the mandibular length between the two groups. 3. Significant differences were found in the mandibular corpus and the ramus between the two groups. In other words, the children in Group A have a narrower ramus, longer corpus and a larger eruption space for the mandibular first permanent molar than the children in Group B. These results indicate that even though there was no significant difference in the anteroposterior dimension of the mandible between the two groups, the internal proportion of the mandible represented as the ratio between the corpus and ramus was significantly different. This may suggest that the different proportional constituents of the mandible have a close relationship with the eruption timing of the mandibular first permanent molar.

Cephalometry↗

PubMed1992

Transcriptional regulation of transferrin and albumin genes by retinoic acid in human hepatoma cell line Hep3B.

Transferrin and albumin, which are both secreted from the human hepatoma cell line Hep3B, were regulated transcriptionally by retinoic acid (RA) in a dose-dependent manner. The cell growth rate was little affected under the same conditions. The treatment of Hep3B cells with RA (10 microM for 48 h) resulted in an 8-fold increase in transferrin protein synthesis, a 10-fold increase in the steady-state transferrin mRNA level, and a 5-fold increase in its transcriptional rate. The same treatment led to 4-fold decrease in albumin synthesis, as well as a 7-fold decline in the steady-state albumin mRNA level and a 4-fold decrease in the transcriptional rate. Cycloheximide and actinomycin D blocked the action of RA, suggesting that RA may regulate transferrin and albumin gene expression indirectly in human liver cells.

Blotting, Northern↗

PubMed1992

Coexistence of autonomic and somatic mechanisms in the pressor areas of medulla in cats.

The effects of electrical stimulation and microinjection of sodium glutamate (0.5 M) in the sympathetic pressor areas of the dorsal medulla (DM), ventrolateral medulla (VLM), and parvocellular nucleus (PVC) on the knee jerk, crossed extension, and evoked potential of the L5 ventral root produced by intermittent electrical stimulation were studied in 98 adult cats anesthetized with chloralose and urethane. During electrical and glutamate stimulation of these pressor areas, in addition to the rise of systemic arterial blood pressure marked inhibition of the spinal reflex was produced, indicating presence of neuronal perikarya responsible for these actions. Mild to moderate augmentation of spinal reflexes was also observed during brain stimulation but only in a few cases. The magnitude of the somatic effects among the pressor areas of the VLM, DM, and PVC subsequent to glutamate activation was about the same. Induced spinal reflex inhibition, independent from the baroreceptor and vagal influence, remained essentially unaltered after acute midcollicular decerebration. The inhibition was also observed in cats decerebellated 8-10 days in advance. The inhibition was not affected after bilateral electrolytic- or kainic-acid-induced lesions in the paramedian reticular nucleus (PRN). On the contrary, PRN-induced spinal reflex inhibition was attenuated after bilateral lesions in the DM or VLM. Data suggest that there coexists neuronal subpopulations in the VLM, DM, and PVC that can affect both the sympathetic pressor systems and spinal reflexes.

Animals↗

PubMed1992

Role of creatine phosphokinase in predicting acute renal failure in hypocalcemic exertional heat stroke.

Recruits frequently develop hypocalcemia in exertional heat stroke (ExHS) with rhabdomyolysis and acute renal failure (ARF) from intensive training. It usually indicated severe skeletal muscle damage. However, the relative risk of ARF in ExHS patients complicated with hypocalcemia was unknown. The present study was undertaken to evaluate the value of peak serum creatine phosphokinase (CPK) level in predicting ARF in ExHS patients with hypocalcemia. Sixty-eight army recruits with ExHS were hospitalized at the Tri-Service General Hospital, Taiwan: 17 with ARF and hypocalcemia (group A); 7 with ARF but without hypocalcemia (group B); 20 without ARF but with hypocalcemia (group C); and 24 without ARF or hypocalcemia (group D). In the 24 patients with ARF (groups A and B) the serum phosphate and peak CPK levels were significantly higher than in patients without ARF (groups C and D; p < 0.001), serum calcium levels were also significantly lower in the former (p < 0.001). In the 37 patients with hypocalcemia (groups A and C), the peak serum CPK levels were significantly higher than in those without hypocalcemia (groups B and D; p < 0.001). There was a higher proportion of hypocalcemic patients with peak serum CPK levels greater than 10,000 U/l among ARF compared with patients without ARF (chi 2 = 12.48, p < 0.001). In 24 patients with ARF, there was a negative correlation between serum Ca and peak CPK levels (t = 3.37, r = -0.58, p < 0.01). However, a positive correlation was found between serum creatinine and peak serum CPK levels in 37 patients with hypocalcemia (t = 2.47, r = 0.39, p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗

PubMed1992

[Masticatory training with chewing gum on young children].

Mastication is a developmental function. It matures through learning experiences. The biting force is one of the components of masticatory function. The biting force increases with age. During the developmental stage, it is believed feasible to enhance the maturation of the masticatory function by increasing the biting force. The previous results of masticatory training for adults and school children had revealed 20% to 30% increase of the biting force. In this study, masticatory training with specially fabricated chewing gum for young (preschool) children was performed. The subjects were 5 males and 5 females from 3 years old to 5 years old. These children were instructed to bite on the chewing gum for 5 minutes, 2 times a day, for 3 months. The results show that there was a 94% average increase of biting force after 3 months of training. It was also noted that the rate of the increase of the biting force was remarkable during the first month of training.

Age Factors↗

PubMed1992

A study on a method to identify the border between mandibular corpus and ramus on lateral cephalometric radiograph.

The mandible has two major parts, the corpus and the ramus. These two parts must be considered separately because each has its own functional counterpart with the maxilla and the posterior cranial base. Since the mandible is a single bone, the border of the corpus and the ramus can not be visualized on the conventional two-dimensional lateral cephalometric radiograph. The purpose of this study is to propose a reliable method to distinguish the border between the mandibular corpus and the ramus on the lateral cephalometric radiograph. In this study, 64 dried skulls in different developmental stages were examined. Metallic markers were placed at the diverging point (point T) on both sides of the dried skulls. From the occlusal view of the mandible, point T was considered to be the lingual border of the corpus and the ramus. Then, the lateral cephalometric radiographs of the dried skulls were taken. On each lateral cephalometric radiograph, a vertical line L was drawn from point Ra (the intersection of the occlusal plane and the anterior border of the ramus) to the mandibular plane. Thus, the distance from the midpoint of point T on each side to the vertical line L was measured. As a result, over 80% of the midpoints T were found on the vertical line L. Therefore, the vertical line L from point Ra to the mandibular plane can be considered to play the role of a reasonable reference line for distinguishing between the corpus and the ramus on the lateral cephalometric radiograph.

Cephalometry↗

PubMed1991

Steroid and benzyl alcohol diffusion through tissue expanders and double lumen breast implants.

The rate of diffusion of benzyl alcohol (the bacteriostatic agent in the provided diluent) and methylprednisolone 21-hemisuccinate and related rearrangement and hydrolysis products ("steroid") through tissue expanders was examined. The rate of diffusion of steroid through double lumen breast implants was also studied. It was found that benzyl alcohol rapidly diffused through tissue expanders into a saline bath. By 24 hours, one-half of the benzyl alcohol had diffused through the expander. The steroid was much slower to diffuse out of the expander. By 141 days, only 2% of the steroid was found in the bath. This rate was comparable for both the tissue expander and double lumen implants. In addition, a significant amount of the steroid is located in the expander wall, associated with the surface of the expander or precipitated out of solution or both. The clinical significance of these findings is discussed.

Benzyl Alcohol↗

PubMed1991

Differential actions of the medial region of caudal medulla on autonomic nerve activities.

1. The inhibitory effects produced by activation of the medial region of caudal medulla on activities of the left and right cardiac sympathetic, vagus and greater splanchnic nerves were studied in chloralose-urethane anaesthetized cats. 2. Electrical stimulation of the medial region produced an 80-92% inhibition of the sympathetic nerve activities, and a 45% and 58% inhibition of the left and right cardiac vagal nerve activities, respectively. There were no significant differences between effects elicited in the left and right autonomic nerves. Similar but smaller inhibitory effects were produced by micro-injection of sodium glutamate (0.5 mol/L) or DL-homocysteic acid (50 mmol/L) to the same medullary sites. 3. These data suggest that neurons residing in the medial medullary region exert strong inhibitory effects on autonomic nerve activities. Since the vasculature is principally innervated by sympathetic nerves, inhibition of sympathetic nerve activities might be the principal factor responsible for the depressor effects caused by activation of the medial region of caudal medulla. The heart is innervated both by sympathetic and parasympathetic nerves. Thus, their simultaneous inhibition during activation of the medial region elicits only a weak and variable inhibition of the heart.

Anesthesia↗

PubMed1990

Inhibition of spinal reflexes by paramedian reticular nucleus.

The inhibitory actions of the paramedian reticular nucleus (PRN), and its neighbouring structures, i.e., midline raphe nuclei (MRN) and dorsal medullary depressor area (DMD) on the knee jerk (KnJ) and crossed extension movement (CEM) induced by central sciatic stimulation and on the L5 ventral root response (EVRR) evoked by central tibial stimulation, were studied in cats under urethane (400 mg/kg) and alpha-chloralose (40 mg/kg) anesthesia alone, IP or further paralyzed with atracurium besylate (0.5 mg/kg/30 min), IV. Electrical stimulation of the above areas with rectangular pulses (80 Hz, 1.0 msec, 100-200 microA) decreased systemic arterial blood pressure (SAP) in an average value of: 36 +/- 3 mmHg for PRN; 19 +/- 2 mmHg for MRN; and 23 +/- 3 mmHg for DMD. The KnJ and CEM were almost completely suppressed by simultaneous PRN stimulation. The EVRR, including mono- and polysynaptic spinal reflexes with transmission velocity from 10 to 60 m/sec or above, were also suppressed. MRN stimulation only inhibited the KnJ, CEM and polysynaptic spinal reflexes with transmission velocities between 25 and 60 m/sec, but facilitated spinal reflexes with conduction velocities below 10 m/sec. On the other hand, DMD stimulation resulted in small suppression of KnJ, CEM and inhibition of polysynaptic spinal reflexes with conduction velocities between 25 and 60 m/sec. Even though MRN and DMD partially inhibited polysynaptic spinal reflexes, the magnitude of such inhibition was much smaller than that produced by PRN (-20% and -22% vs. -48%). The above-mentioned PRN effects on SAP and EVRR persisted in chronic animals decerebellated 9-12 days before.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

The hemodynamics and clinical effects of labetalol in hypotensive anesthesia.

Labetalol is a relatively new and unique hypotensive agent that has both alpha- and beta-adrenoceptor blocking properties. 12 patients in fit physical condition who underwent elective oral surgery were subject to hypotensive anesthesia with labetalol to assess the hemodynamic aspects and clinical effects of the drug. All of them had their anesthesia maintained with halothane and N2O in 50% O2 supplemented by fentanyl and vecuronium. Initiation of deliberate hypotension was made with intravenous bolus of labetalol at 0.5 mg/kg and the ideal level of mean arterial pressure at 55 +/- 5 mm Hg was maintained with adjustment of the concentration of halothane. At the termination of deliberate hypotension, the blood pressure was recuperated to the baseline level by lowering the concentration of halothane and administration of 0.5-0.6 mg intravenous atropine. Our results showed that the total dose of labetalol used was 44 +/- 13 mg and blood loss amounted to 354 +/- 136 ml. Important changes of hemodynamic parameters before and after labetalol included the fall of mean BP, HR, mean PAP, CI, LVSWI, SVRI, PVRI and O2 delivery and the increasing of O2 extraction. As to CVP, PCWP, SVI, O2 consumption and shunting the alterations were minimal. Blood gas analysis showed that, save a slight fall of pH indicating mild metabolic acidosis, the PaO2 and PaCO2 remained unchanged following the use of labetalol. Labetalol-induced hypotension could be effectively reversed by using of atropine as shown in our study and all the patients recovered uneventfully from hypotensive anesthesia. They were entirely free from any complication or sequela relevant to the deliberate hypotension after one year's follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

[Esophageal motility and gastric emptying in PSS patients, correlation with symptoms].

Progressive systemic sclerosis (PSS) commonly involves the esophagus. Dysphagia and heartburn are the most common esophageal symptoms. In this study we evaluated the relationship between esophageal symptoms and esophago-gastric motility. On esophageal manometry, loss of peristalsis, peristaltic contraction amplitude of distal esophagus less than 30 mmHg and decreased LES pressure were critical for esophageal symptoms. The degree of symptoms correlated to esophageal dysmotility. The gastric emptying in PSS patients was delayed, but there was no significant difference in gastric emptying between the patients with and without reflux esophagitis. Esophageal dysmotility is considered to be much responsible for the reflux esophagitis in PSS patients than gastric emptying.

Adult↗

PubMed1989

Evaluation and comparison of the axis of the interventricular septum by two-dimensional echocardiography among the patients with congenital heart disease (ASD, VSD, PDA, PS, TOF) and the normal subjects.

A two-dimensional echocardiographic method was applied to determine the axis of interventricular septum (IVS) in the horizontal plane. This study comprised 19 subjects with ASD, 15 subjects with VSD(I), 20 subjects with VSD(II), 13 subjects with PDA, 16 subjects with PS, 15 subjects with TOF and 99 normal children. Parasternal left ventricular short axis view was taken, and the IVS was recorded by using the polaroid prints. The axis of the IVS in the horizontal plane was measured from the recorded polaroid prints. The value of the angularity of IVS (IVS-A) expressed as means +/- one standard deviation (mean +/- 1S.D.) is 52.0 +/- 13.7 degrees in ASD, 42.2 +/- 9.7 degrees in VSD(I), 43.7 +/- 9.1 degrees in VSD(II), 41.6 +/- 11.4 degrees in PDA, 38.6 +/- 10.9 degrees in PS, 61.0 +/- 8.5 degrees in TOF and 40.1 +/- 8.2 degrees in normal controls. There was no significant difference among VSD(I), VSD(II), PDA, PS and normal controls but a highly significant difference was noted in ASD and TOF as compared to other groups. The correlation coefficient of the IVS-A with (1) the Qp/Qs ratio, (2) the magnitude of shunt (%), (3) the right ventricular pressure and (4) the hematocrits were evaluated among the patient groups. The IVS-A of ASD and VSD(II) had a good correlation with the shunt flow (r = 0.921 and 0.88 respectively) and/or the Qp/Qs ratio (r = 0.782 and 0.955 respectively); while that of VSD(I), PDA, and PS had a good correlation with the right ventricular pressure (r = 0.956, 0.953, 0.842 respectively) and that of TOF was mostly concerned with the hematocrits (r = 0.911). Besides, the IVS-A in each severe CHD subgroup was significantly (p less than 0.005 or a better value) higher than the normal control group. Thus an alternative method was validated for evaluating the severity of congenital heart disease by using a noninvasive two-dimensional echocardiographic technique.

Child↗

PubMed1989

Two-dimensional pulsed Doppler echocardiographic technique for estimating pulmonary to systemic blood flow ratio in children with atrial septal defect and patent ductus arteriosus.

A two-dimensional pulsed Doppler echocardiographic method was evaluated for quantifying the pulmonary (Qp) to systemic (Qs) blood flow ratio. Twenty six patients were studied, 15 with atrial septal defect (ASD) and 11 with patent ductus arteriosus (PDA). An apical four-chamber view was used to measure the maximal Doppler flow velocities in the right and left ventricular inflow regions (RVIR and LVIR) and the maximal diameters of the tricuspid and mitral anuli at diastole. The two-dimensional pulsed Doppler pulmonary to systemic blood flow ratio (Qp/Qs) estimation involved calculating the area of the Doppler flow velocity signal along the time scale multiplied by the diameter of either the tricuspid or mitral anulus as measured on the apical four-chamber view. In ASD patients, Qp was measured at RVIR and Qs at LVIR. In PDA patients, Qp was calculated at LVIR and Qs at RVIR. Twenty-six healthy children comprised the control group. The areas of the Doppler flow velocity signals along the time scales of RVIR and LVIR were also quantified and the diameters of the tricuspid and mitral anuli were measured. In the control group, the linear correlation of the trans-mitral M(d)*M(a) to trans-tricuspid T(d)*T(a) value was r = 0.909, n = 26. The correlations between Doppler Qp/Qs ratio estimates and those obtained at cardiac catheterization were r = 0.902, n = 15 in ASD and r = 0.967, n = 11 in PDA. These results suggest a clinical application of this Doppler echocardiographic method in the noninvasive estimation of the cardiac shunt in ASD and PDA.

Blood Flow Velocity↗